As a general rule codeshares mean OLCI on the operating airline, so Qatar here. Ditto baggage check-in at the airport - that's QR. The big exception would have been if the routing was MAN-LHR-DOH-JRO with BA as the first flight - then you would use the BA Mamage My Booking and you may be able to extract a QR boarding pass. It's not too surprising if OLCI doesn't work, and in any case QR is a bit fixated on printed boarding passes. If you have a ticket number beginning 125 don't worry if OLCI doesn't work. Plus if he is at Uni he should be handling this, not beloved parent!